1. Field of the Invention
The present invention relates to a dispensing apparatus for dispensing two strips of a plastic material, such as a tape, with a differential friction load being imposed on one of the two strips.
2. Description of the Prior Art
The chemical analysis instrument disclosed and claimed in the copending application Ser. No. 642,814, filed Aug. 21, 1984 and assigned to the assignee of the present invention utilizes a pair of ribbon-like strips of plastic material to form chemical analysis cuvettes. The strips are arranged in radially superimposed fashion on a rotating cuvette-forming wheel. The strips are drawn onto the cuvette-forming wheel as the wheel is rotationally advanced.
The inner of the strips is deformed by a jet of heated air into intimate contact with a cuvette molding recess disposed on the periphery of the wheel. The outer strip is tightly stretched in a chordal fashion over the deformed portion of the inner strip. When heat sealed about the contours of the molding recess an analysis cuvette is formed on-site in a cost effective manner.
It is believed to be advantageous to provide a dispensing apparatus for holding the supply spools for both the inner and the outer strip of plastic material used to form the cuvettes. In addition, since the outer strip must be tightly drawn across the edges of the mold recess which receives the inner strip it is important that the dispensing apparatus be adapted to apply a differential friction load on the spool of the outer strip in order to retard the dispensation of that strip with respect to that of the inner strip and thereby to permit the formation of the required chordal relationship for the outer strip.